Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-10-05
2001-12-18
Arbes, Carl J. (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C333S182000, C333S206000, C333S207000
Reexamination Certificate
active
06330741
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This disclosure is related to applications of very high Q cryogenic dielectric resonators at X-band to the development of ultra low phase noise phase noise sources for radar.
2. Description of the Related Art
X-hand dielectric resonators using low order TE
On
modes and higher order whispering gallery modes of a sapphire puck are being developed to work at temperatures ranging from room temperature to cryogenic temperatures. Because the loss tangent of sapphire varies as the fifth power of temperature, lowering the operating temperature to ~77 K (liquid nitrogen) allows Q values of ~10
6
(low order modes), and >10
7
(high order modes) to be realized. To realize the full Q potential at cryogenic temperatures, low loss puck support posts must contact the puck at the center of the flat faces. The resonant electric field amplitudes in and around the puck near the z axis are very small and a post aligned along the z axis will have minimal effect on resonant frequency and resonant Q.
One of our earlier spindle (post) mount sapphire resonators was made out of a single piece of c-axis sapphire. The solid sapphire-puck is contained within a metal cavity as shown in
FIGS. 1
a
and
1
b
and was designed for TE
02
operation at 10 Ghz. The measured Q of this resonator at 77 K was 0.6×10
6
, where we expected 1.0×10
6
. The Q degradation was due to a low quality finish of the flat faces of the puck. These faces could not be properly finished with the spindle in the way. For the next phase of the STALO program we ordered sapphire puck and separated post sets where all faces of the puck had a high quality finish. These pucks were dimensioned for higher order whispering gallery mode operation at X-band because the Q requirements (10
7
) of this phase of the program could not be satisfied with TE
On
modes.
BRIEF SUMMARY OF THE INVENTION
The object of this invention is to provide a technique of bonding crystalline sapphire pieces together.
The technique of shrink fitting technique described herein is used to bond crystalline sapphire pieces to each other, in particular, the shrink fitting of a c-axis sapphire post to a c-axis sapphire puck. The sapphire dielectric resonator is used successfully from cryogenic temperatures to well above room temperature. The shrink fit bond yields a high strength and rigid attachment which can withstand high shock levels. Since there is no loss, the resonator Q is a maximum, being limited by the sapphire loss tangent only.
REFERENCES:
patent: 4276525 (1981-06-01), Nishikawa et al.
patent: 4506241 (1985-03-01), Makimoto et al.
patent: 5500995 (1996-03-01), Palmieri et al.
Weinert Robert
Wright Dexter V.
Arbes Carl J.
Karasek John J.
Stockstill Charles J.
The United States of America as represented by the Secretary of
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